Search found 892 matches

by Joe Farina
Thu Jul 16, 2026 12:49 pm
Forum: DCG
Topic: gelatin turbidity
Replies: 5
Views: 993

Re: gelatin turbidity

Light-Sensitive Systems by Jaromir Kosar https://www.ebay.com/itm/117292548822?_skw=kosar+light+sensitive+systems&itmmeta=01KXP0H7SF6MDJTFADRMDCMNCC&hash=item1b4f2e42d6:g:jgMAAeSwWs1qTvr9&itmprp=enc%3AAQALAAABAGfYFPkwiKCW4ZNSs2u11xDih6d8mri9OpgwPzaVgLyJITLbiGcoQQlAzf8gjgKYxXm2C1KFr1Om%2...
by Joe Farina
Fri Jul 03, 2026 7:29 am
Forum: DCG
Topic: gelatin turbidity
Replies: 5
Views: 993

Re: gelatin turbidity

Thanks for your comments and the pages from the book by Kosar. That book always has something new, no matter how many times I look at it.
by Joe Farina
Wed Jul 01, 2026 5:23 pm
Forum: DCG
Topic: gelatin turbidity
Replies: 5
Views: 993

gelatin turbidity

Having bought a DSLR camera, I wanted to test it here on the forum, by taking a photo of a graph obtained from Google AI. My last SLR was a silver halide film camera in the 1990's. Technology sure does move fast with regards to cameras. This is just an entry-level Olympus OM-D E-M10 Mark IV, but the...
by Joe Farina
Tue Jun 02, 2026 2:50 pm
Forum: DCG
Topic: A long post about bubbles
Replies: 9
Views: 17884

Re: A long post about bubbles

Hi Tony, thanks for the tip, I will keep it in mind. I was using plastic syringes which had silicone oil (presumably) to lubricate the rubber portion of the plunger. Pits resulted after using this (with a syringe filter), but no pits were seen when the emulsion wasn't filtered with the syringe. The ...
by Joe Farina
Wed May 27, 2026 4:25 pm
Forum: Gallery
Topic: today's DCG
Replies: 29
Views: 679298

Re: today's DCG

This is the same hologram reprocessed with 68C 100%. Much brighter, without any noticeable difference in bandwidth. Thanks for reminding me! In transmitted light, the plate is clear. For some reason the camera is picking up some blue glare which is mostly absent when viewing the hologram by eye. It'...
by Joe Farina
Wed May 27, 2026 7:04 am
Forum: Gallery
Topic: today's DCG
Replies: 29
Views: 679298

Re: today's DCG

Thanks for your thoughts about the warm water bath. So far in my tests, a wavelength shift upward (towards red) is preferable to a blue shift, because there are methods (such as prolonged baking) which can shrink the layer back down. On the other hand, if there is too much shrinkage, it's quite chal...
by Joe Farina
Mon May 25, 2026 11:23 am
Forum: Gallery
Topic: today's DCG
Replies: 29
Views: 679298

Re: today's DCG

A (still blurry) photo showing blue figure on left. The previous hologram was re-processed today with a higher water temperature. My beam alignment (reflecting off the spherical mirror) was off: too much green on the right, and too much blue on the left.
P1010043.JPG
P1010043.JPG (430.71 KiB) Viewed 23189 times
by Joe Farina
Sun May 24, 2026 2:37 pm
Forum: Gallery
Topic: today's DCG
Replies: 29
Views: 679298

Re: today's DCG

I had problems focusing the photo, the figure on the right was focused, the others weren't. This is a two-color DCG hologram done today. Still trying to find a film formula that is reproducible, but I've made quite a bit of progress in the last couple days. P1010037.JPG This test hologram was re-pro...
by Joe Farina
Sat Apr 25, 2026 4:54 pm
Forum: DCG
Topic: Crystallization problems w/ Dip-n-shoot or G307
Replies: 3
Views: 23457

Re: Crystallization problems w/ Dip-n-shoot or G307

Thanks Dave, that makes good sense. Part of my problem was over-loading the emulsion with dichromate when exposing at 488nm, as you suggested. I watched the plate as it was being exposed and saw a huge amount of scatter coming off the emulsion (it looked a little like frosted glass) when being expos...
by Joe Farina
Tue Apr 21, 2026 8:51 am
Forum: DCG
Topic: Crystallization problems w/ Dip-n-shoot or G307
Replies: 3
Views: 23457

Crystallization problems w/ Dip-n-shoot or G307

I've had some crystallization problems with G307. It may be due to the cool temp of 16C (60F) used when drying. When immersing the gelatin layer in the 5% solution of potassium dichromate (with a little glycerol and Photo-flo), it comes out clear, but after drying a while, white crystals form, espec...